Preheat the oven to 350 degrees F. Grease a 9x13 inch baking dish.
In a large mixing bowl, beat together the butter, brown sugar and sugar until combined. Add the eggs, vanilla and instant coffee, beat until combined and creamy. Add the flour, baking soda, and salt and beat until combined. Stir in 2 cups chocolate chips.
Spread the dough out in the prepared baking pan. Transfer to the oven and bake for 18-20 minutes, just until set in the center. Allow to cool.
To make the caramel, in a large, dry, deep, heavy pot, cook the sugar over moderately high heat, stirring constantly with a heat proof rubber spatula until the sugar is melted and turns a golden caramel, about 8 minutes. Remove the pot from the heat and let cool 5 minutes. Slowly add the chunks of butter in one by one, whisk until combined. The caramel will bubble, this is ok. Now slowly add the cream and then whisk until combined. Return the pot to moderate heat and cook the mixture, stirring until the caramel has thickened, about 5 minutes, or until the caramel reaches 235-240 degrees F. on a sugar thermometer. Remove from the heat, if using, add the Kahlua + a pinch of salt. Let cool 5 minutes and then pour the caramel over the cookie bars. Let the bars set at least 30 minutes.
Melt the remaining 2-3 cups chocolate chips in the microwave or over a double broiler. Sprinkle the Rice Krispies over the caramel layer and then pour the melted chocolate over top. Place the bars in the fridge to set, about 15-20 minutes. Cut the bars into squares. Serve at room temperature. Store in the fridge or in a cool, dark spot in your kitchen.